42,645 research outputs found

    Black and minority ethnic sex offenders

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    In the past ten years or so there has been a growing concern that the treatment needs of Black and Minority Ethnic (BME) sex offenders in prison are not being appropriately met. Underpinning this concern is the continued under representation of BME sex offenders on the Sex Offender Treatment Programme (SOTP). Although some research has been undertaken into how BME prisoners experience the SOTP and in to its ostensible effectiveness with BME sex offenders, little is known about why the take-up of the SOTP is poor with this group. In this paper we first consider some specific demographic issues that need to be understood in order to reflect more widely on the BME sex offender in prison. We then summarise what is currently known about effective practice with this group, thereafter we consider, in turn, current provision for BME sex offenders in England and Wales and suggestions for developing practice with this group of men. However, before we turn to these issues, it is important to consider briefly issues of terminology. Terminologies in relation to ethnicities and race are fraught with conceptual difficulties. Aspinall has highlighted the limitations of ‘pan-ethnic’ groups, such as ‘BME’; such groupings are ‘statistical collectivities’ and ‘the groups thus defined will be nothing more than meaningless statistical collectivities that do not represent any of the constituent groups within the term.’ . However, at the outset of this paper we use the collective term BME - this term is currently used by a number of Government Departments in the UK, including the Prison Service. Later we suggest that a more sophisticated understanding of ethnic cultures may be necessary to develop practice with BME sex offenders.</p

    BME sex offenders in prison: the problem of participation in offending behaviour groupwork programmes – a tripartite model of understanding

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    This paper addresses the under representation of Black and minority ethnic (BME) sex offenders in the sex offender treatment programme (SOTP) of the prisons of England and Wales. The proportional over representation of BME men in the male sex offender population of the prisons of England and Wales has been noted for at least ten years. Similarly the under representation of BME sex offenders in prison treatment programmes has been a cause for concern during the last decade. This paper presents current demographic data relating to male BME sex offenders in the prisons of England and Wales. The paper draws together a wide range of social and cultural theories to develop a tripartite model for understanding the dynamics underlying the non-participation of BME sex offenders in therapy.</p

    Contamination of stellar-kinematic samples and uncertainty about dark matter annihilation profiles in ultrafaint dwarf galaxies: the example of Segue I

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    The expected gamma-ray flux coming from dark matter annihilation in dwarf spheroidal (dSph) galaxies depends on the so-called `J-factor', the integral of the squared dark matter density along the line-of-sight. We examine the degree to which estimates of J are sensitive to contamination (by foreground Milky Way stars and stellar streams) of the stellar-kinematic samples that are used to infer dark matter densities in `ultrafaint' dSphs. Applying standard kinematic analyses to hundreds of mock data sets that include varying levels of contamination, we find that mis-classified contaminants can cause J-factors to be overestimated by orders of magnitude. Stellar-kinematic data sets for which we obtain such biased estimates tend 1) to include relatively large fractions of stars with ambiguous membership status, and 2) to give estimates for J that are sensitive to specific choices about how to weight and/or to exclude stars with ambiguous status. Comparing publicly-available stellar-kinematic samples for the nearby dSphs Reticulum~II and Segue~I, we find that only the latter displays both of these characteristics. Estimates of Segue~I's J-factor should therefore be regarded with a larger degree of caution when planning and interpreting gamma-ray observations. Moreover, robust interpretations regarding dark matter annihilation in dSph galaxies in general will require explicit examination of how interlopers might affect the inferred dark matter density profile.Comment: 12 pages, 8 figures. New appendix A (joint light/dark matter likelihood), results unchanged. Match accepted MNRAS versio

    A Lattice Test of 1/N_c Baryon Mass Relations

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    1/N_c baryon mass relations are compared with lattice simulations of baryon masses using different values of the light-quark masses, and hence different values of SU(3) flavor-symmetry breaking. The lattice data clearly display both the 1/N_c and SU(3) flavor-symmetry breaking hierarchies. The validity of 1/N_c baryon mass relations derived without assuming approximate SU(3) flavor-symmetry also can be tested by lattice data at very large values of the strange quark mass. The 1/N_c expansion constrains the form of discretization effects; these are suppressed by powers of 1/N_c by taking suitable combinations of masses. This 1/N_c scaling is explicitly demonstrated in the present work.Comment: 13 pages, 20 figures; v2 version to be published in PR

    Neutrinoless double beta decay in effective field theory: the light Majorana neutrino exchange mechanism

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    We present the first chiral effective theory derivation of the neutrinoless double beta-decay nn→ppnn\rightarrow pp potential induced by light Majorana neutrino exchange. The effective-field-theory framework has allowed us to identify and parameterize short- and long-range contributions previously missed in the literature. These contributions can not be absorbed into parameterizations of the single nucleon form factors. Starting from the quark and gluon level, we perform the matching onto chiral effective field theory and subsequently onto the nuclear potential. To derive the nuclear potential mediating neutrinoless double beta-decay, the hard, soft and potential neutrino modes must be integrated out. This is performed through next-to-next-to-leading order in the chiral power counting, in both the Weinberg and pionless schemes. At next-to-next-to-leading order, the amplitude receives additional contributions from the exchange of ultrasoft neutrinos, which can be expressed in terms of nuclear matrix elements of the weak current and excitation energies of the intermediate nucleus. These quantities also control the two-neutrino double beta-decay amplitude. Finally, we outline strategies to determine the low-energy constants that appear in the potentials, by relating them to electromagnetic couplings and/or by matching to lattice QCD calculations.Comment: 20 pages, 6 figure

    Spherical Jeans analysis for dark matter indirect detection in dwarf spheroidal galaxies - Impact of physical parameters and triaxiality

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    Dwarf spheroidal (dSph) galaxies are among the most promising targets for the indirect detection of dark matter (DM) from annihilation and/or decay products. Empirical estimates of their DM content - and hence the magnitudes of expected signals - rely on inferences from stellar-kinematic data. However, various kinematic analyses can give different results and it is not obvious which are most reliable. Using extensive sets of mock data of various sizes (mimicking 'ultra-faint' and 'classical' dSphs) and an MCMC engine, here we investigate biases, uncertainties, and limitations of analyses based on parametric solutions to the spherical Jeans equation. For a variety of functional forms for the tracer and DM density profiles, as well as the orbital anisotropy profile, we examine reliability of estimates for the astrophysical J- and D-factors for annihilation and decay, respectively. For large (N > 1000) stellar-kinematic samples typical of 'classical' dSphs, errors tend to be dominated by systematics, which can be reduced through the use of sufficiently general and flexible functional forms. For small (N < 100) samples typical of 'ultrafaints', statistical uncertainties tend to dominate systematic errors and flexible models are less necessary. We define an optimal strategy that would mitigate sensitivity to priors and other aspects of analyses based on the spherical Jeans equation. We also find that the assumption of spherical symmetry can bias estimates of J (with the 95% credibility intervals not encompassing the true J-factor) when the object is mildly triaxial (axis ratios b/a = 0.8, c/a = 0.6). A concluding table summarises the typical error budget and biases for the different sample sizes considered.Comment: 21 pages, 20 figures. Minor changes (several clarifications): match the MNRAS accepted versio

    A Supersymmetric Flipped SU(5) Intersecting Brane World

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    We construct an N=1 supersymmetric three-family flipped SU(5) model from type IIA orientifolds on T6/(Z2×Z2)T^6/(\Z_2\times \Z_2) with D6-branes intersecting at general angles. The spectrum contains a complete grand unified and electroweak Higgs sector. In addition, it contains extra exotic matter both in bi-fundamental and vector-like representations as well as two copies of matter in the symmetric representation of SU(5).Comment: 17 pages, 3 tables, v2 published in Phys.Lett.

    Protective telescoping shield for solar concentrator

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    An apparatus is described for use with a solar concentrator such as a parabolic dish which concentrates sunlight onto a small opening of a solar receiver, for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved to a stowed position where it does not block sunlight, to a deployed position. In this position, the structure forms a tube which substantially completely surrounds an axis connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator

    Inference of epidemiological parameters from household stratified data

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    We consider a continuous-time Markov chain model of SIR disease dynamics with two levels of mixing. For this so-called stochastic households model, we provide two methods for inferring the model parameters---governing within-household transmission, recovery, and between-household transmission---from data of the day upon which each individual became infectious and the household in which each infection occurred, as would be available from first few hundred studies. Each method is a form of Bayesian Markov Chain Monte Carlo that allows us to calculate a joint posterior distribution for all parameters and hence the household reproduction number and the early growth rate of the epidemic. The first method performs exact Bayesian inference using a standard data-augmentation approach; the second performs approximate Bayesian inference based on a likelihood approximation derived from branching processes. These methods are compared for computational efficiency and posteriors from each are compared. The branching process is shown to be an excellent approximation and remains computationally efficient as the amount of data is increased
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